Fixing standalone bundles requirements

When you try to install a bundle standalone (v1.0.*@dev), you get 
```
PHP Fatal error:  Class 'Doctrine\Bundle\DoctrineBundle\DependencyInjection\Compiler\DoctrineOrmMappingsPass' not found in /home/jago/testtoto/vendor/sylius/cart-bundle/Sylius/Bundle/CartBundle/SyliusCartBundle.php on line 55
```